The invention relates to a machine for the pneumatic spreading of granular material, which is constructed for mounting on a farm tractor and is equipped with a central hopper and tubes some of which extend beyond the hopper transversely of the direction of movement of the tractor, and which are connected by an air duct to a blower mounted on the machine and driven by the power take-off shaft of the tractor carrying the machine, the material being fed to the said tubes from the hopper through outlet openings and a metering device driven by a regulating drive, the said tubes having discharge openings at their outer extremities which are disposed at intervals transversely of the direction of movement of the tractor, the hopper being divided in its lower area by a roof-shaped plate into a forward and a rearward section, the said sections being provided with the said discharge openings and with metering devices.
A machine of this kind is known through German "Auslegeschrift" 23 19 940. This machine has proven to be practical, but it has the disadvantage mainly that it is relatively long, so that, when mounted on the tractor, its center of gravity is located so far in back of the machine that, in order to lift it into the working position with the hopper filled, a lifting force is required which can be supplied only by the power lift systems of heavy and powerful tractors.
Even in the case of such tractors as these, there is the danger that the weight will be removed from their front wheels to such an extent, when the machine is in the raised position, that it will no longer be possible to hold the tractor precisely on the desired course of travel.